We’ve started off the year with a key step in our process to get ready for Exploration Mission-1, when together Orion and SLS will travel farther than a spacecraft built for humans has ever traveled. This brings us closer to our goal of testing our deep space exploration systems in the proving ground of lunar space before we begin sending astronauts days to weeks from Earth.

The Orion pressure vessel consists of seven large aluminum pieces. In September 2015 engineers began welding them together -- a very meticulous process.

Each element was prepped with strain gauges and wiring to monitor the metal during the process. The pieces were then joined using a state-of-the-art process called friction-stir welding.

Whereas most welding techniques liquefy the metal, this type of welding heats the aluminum to a near-liquid state -- transforming the metal from a solid into a plastic-like state just below the melting point. Its done by using a rotating pin tool which first stirs and softens the metal before forging a bond and creating an incredibly strong, and uniform, joint between the components.

As Mark Kirasich, Orion program manager, said:

The team at Michoud has worked incredibly hard produce a lightweight, yet incredibly durable Orion structure ready for its mission thousands of miles beyond the moon. The work to get us to this point has been essential. Orion’s pressure vessel is the foundation on which all of the spacecraft’s systems and subsystems are going to be built and integrated.

Now that the Orion pressure vessel, which provides a sealed environment in which astronauts will survive, is complete, the structure will be shipped to Kennedy Space Center in Florida where engineers will begin testing to make sure it is sound and can endure the harsh conditions it will meet in deep space.

Following a pressure proof test, the team will then outfit the crew module with all of the avionics and systems the spacecraft will need before being integrating it with the SLS rocket and readying it for launch on it's first mission -- Exploration Mission-1 (EM-1), an uncrewed launch that will pave the way for future missions with astronauts.

This first mission of the SLS/Orion spacecraft is an uncrewed launch that will takeoff from an upgraded and modernized spaceport at Kennedy, launchpad 39B, for a three-week mission that will place the Orion capsule in an orbit thousands of miles beyond the moon.

Putting Orion in such a high orbit well beyond the moon will do two things:

Give NASA a proving ground for testing and managing technologies for crewed flight farther from Earth than any other crew-capable spacecraft since Apollo, and

Demonstrate the capsule can get to a stable orbit.

Both are key to demonstrating the system's capabilities as part of NASA's Journey to Mars.